Landmark recognition and retrieval: from 2D to 3D

Existing landmark retrieval methods cannot provide a comprehensive solution, by which user can view different angles of landmark. In this paper, we propose a novel approach to reconstruct and retrieve 3D landmark models by direct 2D to 3D matching. In an offline module, firstly, attention-based 3D reconstruction method is proposed to reconstruct sparse 3D landmark models. Secondly, we construct textured 3D landmark model for each sparse 3D landmark model. Finally, a 3D landmark recognizer is built for each landmark based on the 3D landmark model. In online module, query images are recognized by the 3D landmark recognizers using a 2D to 3D matching approach. For each recognized query image, a 3D landmark model and a 3D landmark texture model are presented as a query result. Experimental results demonstrate the effectiveness of our proposed approach.